Spinodal-assisted crystallization in polymer melts

TL;DR

This paper proposes a theoretical explanation for spinodal-assisted crystallization in polymer melts, suggesting a coupling between density and chain conformation induces a hidden binodal, with shear influencing the process.

Contribution

It introduces a phenomenological model linking density and chain conformation to explain spinodal kinetics in polymer crystallization.

Findings

Coupling induces a liquid-liquid binodal within the coexistence region.

Shear enhances the kinetic role of the hidden binodal.

Testable predictions are discussed.

Abstract

Recent experiments in some polymer melts quenched below the melting temperature have reported spinodal kinetics in small-angle X ray scattering before the emergence of crystalline structure. To explain these observations we propose that the coupling between density and chain conformation induces a liquid-liquid binodal within the equilibrium liquid--crystalline solid coexistence region. A simple phenomenological theory is developed to illustrate this idea, and several experimentally testable consequences are discussed. Shear is shown to enhance the kinetic role of the hidden binodal.